With regard to the prior art of drive belts, which may be formed as flat belts, V belts, V-ribbed belts and toothed belts, the V-ribbed belts being of particular significance, reference is made particularly to the following patent literature: German patent publications 3,823,157 A1 and 44 00 434 A1; European patent publications 0,599,145 B1 and 1,129,308 B1; U.S. Pat. Nos. 7,128,674; 6,419,775; 6,464,607; 5,413,538 and 3,981,206; and, United States patent application publications 2008/0261739 A1; 2007/0240658 A1; and, 2008/0032837 A1.
German patent publication 38 23 157 A1 describes flocking V-ribbed belts with cotton or aramid on the working side that is susceptible to wear. It has been found that such flocking concepts are not very durable in the case of some engines. Although this type of coating reduces noise problems, in the case of some engines the noise level is still too high, particularly in the case of noise problems when wet.
Therefore, U.S. Pat. No. 3,981,206 proposes a solution whereby the V-ribbed belt is provided with a knit textile overlay of synthetic plastic materials, particularly yarns of two synthetic plastic materials. Here, too, the occurrence of noise when wet is disadvantageous.
From the viewpoint of V-ribbed belts, United States patent application publication 2008/0261739 A1 discloses a more recent development. For, the purpose of improving noise behavior, the textile overlay comprises a knit of two different yarns in the form of different filament modules, particularly in the combination of polyamide (PA) and polyurethane (PU, for example Elasthane). In spite of a considerable increase in resistance, and consequently in the performance in comparison with the state of the art of V-ribbed belts referred to above, here too noises occur in the wet, albeit no longer to the extent previously known.
United States patent application publication 2008/0032837 discloses a toothed belt with a textile overlay of woven fabric which is also referred to here as a tooth overlay. The fabric is a blended fabric based on a polyamide fabric in which the weft threads are entirely or partly replaced in the peripheral/longitudinal direction of the belt by threads of polyether ether ketone (PEEK), polyimide (PI) and/or meta-aramid or are modified with PEEK, PI and/or meta-aramid. In this way, the heat resistance of the toothed belt is increased and a malfunction prevented.
United States patent application publication 2007/0240658 likewise describes a toothed belt with a textile overlay, particularly based on polyamide (for example PA66), which however is coated with a fluoropolymer (for example PTFE), particularly in combination with an additional adhesive layer. The object here is to improve the oil resistance of the toothed belt.
German patent publication 44 00 434 A1 and U.S. Pat. No. 6,419,775 disclose drive belts having a textile overlay in the form of a reinforcing fabric which is likewise coated with a fluoropolymer (for example, PTFE). The object here is to provide a belt surface that has favorable antifriction properties.
German patent publication 44 00 434 A1, European patent publications 0,599,145 B1 and 1,129,308 B1 and U.S. Pat. Nos. 7,128,674; 6,464,607 and 5,413,538 are directed to the technological field of drive belts, that is, in the context of elastomeric materials (for example, HNBR), embedded tension load-bearing elements (for example, steel, polyamide or polyester cords), the use of fibers (for example, aramid or cotton fibers) and the types of drive belts.